MESA 7c81 HELP!

I have a good bit of experience with CNC... built 2 machines in the past... one Mach3 another GRBL.  Long time linux admin.  Have built lots of things with RPI, New to LinuxCNC.

I am refactoring a vertical mill that I converted to CNC and Mach 3 several years ago to use LinuxCNC.  In the past I used a UC ETH-300 which of course is not compatible with LinuxCNC.  So I bought a Mesa 7c81 and an 8gb Raspberry Pi 4.

I have everything connected, Installed LinuxCNC 2.9.2 using the RPI image, have enabled SPI and it appears that I am talking to the Mesa card.
I have a standard chinese BOB connected to port 1 and plan to use ports 2 and 7 for home/limit switches, probe, spindle etc.

Started with pncconf selected my card and the 5ABOB3 firmware, looked up my stepper drivers for time, space, hold etc... 

Cannot figure out the P1, P2, P7 Mesa Card config pages as far as pins goes... expecting to assign pin2 for step X etc...  according to the BOB documentation.
I have assigned the Axis StepGen's to P1 0:, 1:, and 2: just to be able to write the config out.
When I try to test/tune an axis I hear the relay trip on the BOB which is encouraging... and when I try to jog I see the numbers changing on the Hal Meter etc but I get nothing from my steppers... they do feel slightly warm so I believe there is current going to them... but no movement at all

if I try to launch LinuxCNC using the config pncconf created I see some errors come up
"Unexpected realtime delay on task0 with period 70000" and hm2/hm2_7c81.0 Watchdog was bit.

My plan is to get basic stuff working and then add complexity... 

Wondering if anyone has a config they would be willing to share?

Or advice on where to go next... been googling and searching my tail off and figure there is something basic I am missing and once I see it properly configured I will have a big DUH moment

Any help would be appreciated!

You can get a mapping of stepgen numbers (what pncconf shows) to pins
by looking at the .pin file that matches your current firmware.
( probably 7c81_5abobx3d.pin )

The real time delay is because you have a much faster than normal servo
thread rate (normally you would use 1 ms = 1000000 ns period = 1 KHz)

Probably the most common reason for lack of motion on step drives
is too short step pulse width.

Ok I changed the "actual servo period" to 1000000 in pncconf

Feeling not to smart at the moment... where do I find "step pulse width" in pncconf and I have searched the file system and do not see any files starting with 7c81

Sorry for the dumb questions... my google foo needs some help for this kind of stuff

I think that the pulse width is called "Step  On-Time" in pncconf

The firmware and pin files are in this zip file:

www.mesanet.com/software/parallel/7c81.zip
 

In the sample configs included with linuxcnc, you can see examples here

github.com/LinuxCNC/linuxcnc/blob/master...tepper/7i90.ini#L127
github.com/LinuxCNC/linuxcnc/blob/master...tepper-rpspi.hal#L80

Ok upped the Step ON-Time for my X axis  to 20000 and still no movement.

Here is the BOB I am using www.amazon.com/gp/product/B0093Y897A/ref...h_asin_title?ie=UTF8

I am going to attach my hal, ini and pncconf files.  Hopefully, someone can get me out of the ditch.



 

You might take a LED+resistor or DVM and check that the
direction pin changes state when jogging in different directions.

I would probably also change:

loadrt hm2_rpspi config="firmware=hm2/7c81/5ABOBX3.BIT num_encoders=1 num_pwmgens=3 num_stepgens=10"

to:

loadrt hm2_rpspi config="num_encoders=1 num_pwmgens=0 num_stepgens=3"

Unless you need a PWMgen or encoder or 10 stepgens

Changing the encoders pwm gens and step gens made a HUGE difference...

Not sure I understand why... sounds like I need to do some reading on how that driver or maybe linuxcnc works... recommendations?

My steppers now move... unfortunately they are stuttering and making a horrible noise.... I suspect that is all about tuning the settings. If so can you point me to a document on how to develop the tuning parameters?

THANKS!!

You have the PID P terms set so high that they will cause oscillation.

You should use 1/servo-period which is the pncconf default = 1000
for a 1ms servo thread rate.

The physical meaning of a 1/servo thread P term is that position errors
are corrected by the next servo thread invocation. A value of 10000
(with a 1ms servo thread rate) means that a sensed stepgen position
error will be overcorrected by a factor of 9, leading to oscillation.

In addition:

setp hm2_7c81.0.dpll.01.timer-us -50

should probably be changed to

setp hm2_7c81.0.dpll.01.timer-us -200